Aerial for wireless telegraphy.



E. GIRARDEAU.

AERIAL FOR WIEELEss TELEGRAPHY.

APPLICATION FILED 00T.22, 1912.

1 7 Patented June 23, 1914 FIG-.1; Flea- 14 Inventor 53 e Witnesses.- WWJQ; Mmd, 7 l L f Attorney STATES PATENT OFFICE.

EMILE GTRARDEAU, or PARIS, FRANCE, ASSIGNOR or bNE-HALF 'ro JOSEPH BETHENOD, or PARIS, FRANCE.

AERIAL FOR WIRELESS TELEGRAPHY.

Specification of Letters Patent.

Application filed October 22, 1912. Serial No. 727,129.

To all whomit mag concern:

Be it known that I, Eurnn GIRARDEAU, a citizen of the Republic of France, residing at 128 Rue La Botie, Paris, in the French Republic, have invented a certain new and useful Improvement in Aerials for Vireless Telegraphy, of whichithe following is a specification.

As is known the employment of high frequency alternating current generators for directly producing electromagnetic waves would present considerable advantages as compared with the production by the sudden 1 discharge of acondenser by means of a spark gap or some similarly acting device. Unfortunately the production of alternating current generators for frequencies exceeding 10,000 periods per second is attended with great difiiculty, so thatit becomes necessary to provide aerial structures with a wave length of 30 km. and more.

The present invention has for its object an antenna of thiskind'which can be constructed in a relatively economical manner.

An embodiment of the invention is illustrated in the accompanying drawing, in which: a

Figure 1 is a plan of the antenna. Fig. 2 represents a corresponding elevation. Fig. 3. illustrates the ease in which a plurality of antennae mounted in parallel, is available.

The wire F proceeding from the station S is composed in the known manner of two entirely different parts, that is to say of the part '0 which constitutes the eifective (wave radiating) part and of a second horizontal part it, which radiates no waves .In accordance with the present invention the latter consists of a conducting wire stretched in 'the form of a horizontal spiral. This may be effected for example by means of disk-shaped insulators I carried by connect-- ing tensioning cables. If the total length of the horizontal wire it be designated L, the wave length of the antenna would amount to ZZ4L (see J. Zenneck, Le'itfaden der Dmhtlosen Telegraphic, chapter 11, page 38. 25). It will, therefore, be obvious that Patented June 23, 191 4. I

in using masts P of moderate height (say up to 100 m.) and spacing them at the same distance as an antenna, with the usual extent of horizontal network, the wave lengths thus obtained may be very considerable.

It will of course be understood that the form of the spiral antenna can be modified as desired, without thereby affecting the principle of the invention. Thus for example the number of masts can vary as desired and each part '0 or it can consist of a plurality of wires connected in parallel.

I The mode of realization of antennae according to the present invention can of course be applied to obtain all wave lengths,

above or below the number of 30 km. cited aforesaid as example, either they are destined for high frequency alternating current generator stations or for other systems as those using the oscillating discharge of a condenser or other phenomenon. It is also possible, as shown in Fig. 3, which is given by way of example, to mount in parallel a number of antennm arranged either in the same plane or in different planes.

If necessary a wire may be employed for joining the extremities of a number of an:

tenntc thus combined in order to balance the tension at the extremity of the wires.

lVhat I claim and desire to secure by Letters Patent of the United States is An antenna for wireless telegra'phy stations with high frequency alternating current generators, in which the conducting wire or wires consists of two parts, one part which forms the active part and a. generally 

